docs: def create_dirs(self):
          """
          Creates the store directory and its subdirectories.
          """
          if not os.path.isdir(self._path):
              os.makedirs(self._path)
          for dir_name in [self.OBJ_DIR, self.TMP_OBJ_DIR, self.PKG_DIR, self.CACHE_DIR]:
              path = os.path.join(self._path, dir_name)
              if not os.path.isdir(path):
                  os.mkdir(path)
          if not os.path.exists(self._version_path()):
              self._write_format_version()